Gradients of drive stimulus (Sd) intensity generalization.

The effect of change in drive level on habit reversal.

“…The test of number of Ss falling above and below the median number of reversal responses on the last three trials of the first day of reversal learning shows that the changed-drive Ss make more new responses than do the unchanged-drive Ss (x 2 = 4.05, df=l,P< .05). This finding is similar to that of an earlier study (10) in which a decrement in habit strength resulted from a change in drive level as would be predicted by Hull's theory (2).…”

Effect of pairing a stimulus with presentations of the UCS on the extinction of an avoidance response in humans.

“…Studies of the extinction of nonavoidance behavior lend support to this hypothesis. The relevant literature indicates that extinction is facilitated by increasing differences between acquisition and extinction situations in a number of variables, e.g., amount of reinforcement (Lewis & Duncan, 1957), frequency of reinforcement (Lewis & Duncan, 1957), intertrial interval (Reynolds, 1945), and deprivation level (Yamaguchi, 1952). It is possible that the rate of extinction of avoidance behavior is similarly sensitive to differences between acquisition and extinction.…”

Drive Shifting Prior to Extinction of Bar Pressing Reinforced by Different Sucrose Incentives

“…3. One interpretation for this comes from Yamaguchi (1951), who observed chat gradieccs of drive stim~llus generalization were flatter when drive level was increased than when it was decreased. The lowered response potential due to drive scimu~us change was offset by the increased level of drive following the shift.…”